Plate-shaped electrode portions to which terminals of electric components such as sensors and the like are connected are provided on a circuit board which is used in a control unit of a vehicle brake hydraulic pressure control unit. Then, the electric components can be electrically connected to the electronic circuit by the terminals of the electric components being pressed against the electrode portions.
The electrode portion of the circuit board may include a pad which is soldered to a land provided on a front surface of a substrate.
In soldering the pad to the land, a reflow system is used in which a paste solder is applied to the front surface of the land, and the pad is superposed on the solder layer, thereafter the substrate is heated.
JP-4618298-B describes a self-alignment effect working in the soldering step of soldering the pad to the land in which the surface tension of the molten solder in the solder layer acts on the pad to move the pad directly above the land.
In soldering the pad to the land, although the pad can be moved directly above the land by means of the self-alignment of the solder layer, when the pad is disposed directly above the land, the surface tension of the solder layer does not act on the pad. Consequently, in case an impact or vibration is applied to the substrate in such a state that the pad is disposed directly above the land and the solder is melted, a problem will be caused that the pad is easily moved from the aligned state with the land.